Levinsenia flava (Strelzov, 1973)

(Fig. 5)

Tauberia flava Strelzov, 1973: 144 –145, fig. 65A–C.

Levinsenia flava .— Aguirrezabalaga & Gil 2009: 633 –634, figs 2–3.

Material examined. 1612 Sygna SY–01; 61.4635°N–1.9944°E; 297 m; 11.06.1999; one specimens. 1612 Sygna Sy–10; 61.4706°N–1.9948°E; 298 m; 0 9.06. 1999 10–3; one specimen.

Description. The two specimens complete, up to 6.5 mm long, 0.22 mm wide for 57 chaetigers. Body slender, cylindrical. Prostomium conical, twice longer than wide; median antenna absent; pair of nuchal organs as nearly parallel, deep nuchal slits; apical sensory organ as a retractile papilla (Fig. 5A). Notopodial postchaetal lobes as short, rounded tubercles in prebranchial and branchial regions (Fig. 5A); in postbranchial region progressively longer and more slender (Fig. 5B), eventually becoming digitiform and bearing a distal swelling (Fig. 5C).

Neuropodial postchaetal lobes absent. Branchiae from chaetiger 6, three pairs, triangular and very short (twice longer than wide). Noto- and neurochaetae as gently curved limbated capillaries in prebranchial and branchial regions (Fig. 5A); in postbranchial region notochaetae progressively thinner and straighter (Fig. 5B, C); modified neurochaetae from chaetiger 12, strongly hooked and without sheath, numbering 2–4 and accompanied by 1–2 very thin capillaries (Fig. 5B, C). Pygidium biannulated (Fig. 5D); proximal half bearing a dorsal, unpaired cirrus, one and a half as long as complete pygidium; distal half clearly conical.

Remarks. The specimens examined for this study fit well both the original description based on New Guinean material (Strelzov, 1973) and the more recent diagnosis by Aguirrezabalaga & Gil (2000), which was based on material from Europe. Levinsenia flava is characterized by having few pairs of branchiae (three to five) that are very short, clearly shorter than the distance between bases, and by the shape of the modified neurochaetae, which are strongly curved and less protruding than in the rest of species within the genus. Only two other species within the genus possess similarly low number of short branchiae: L. brevibranchiata (Strelzov, 1973) and L. kantaurensis Aguirrezabalaga & Gil, 2009 . The first one was also described from New Guinea, but can be distinguished from L. flava by having a slightly higher number of branchiae (six pairs), by presenting seven instead of five prebranchial chaetigers, and by bearing clearly thicker notopodial postchaetal lobes in branchial chaetigers (Strelzov, 1973). Levinsenia kantaurensis is a more similar species, but it differs from L. flava in the shape of modified neurochaetae, strongly curved in the latter and longer and less curved in the former (Aguirrezabalaga & Gil, 2009).

Distribution. Sea of New Guinea (Strelzov, 1973). Bay of Biscay (Aguirrezabalaga & Gil, 2009). Northern California (Blake et al., 2009). First record for Norway and adjacent waters.